title: Short-term weight loss and hepatic triglyceride reduction: evidence of a metabolic advantage with dietary carbohydrate restriction.
abstract: BACKGROUND
  Individuals with nonalcoholic fatty liver disease (NAFLD) have excess intrahepatic triglycerides. This is due, in part, to increased hepatic synthesis of fat from carbohydrates via lipogenesis. Although weight loss is currently recommended to treat NAFLD, little attention has been given to dietary carbohydrate restriction.
  
  
  OBJECTIVE
  The aim of this study was to determine the effectiveness of 2 wk of dietary carbohydrate and calorie restriction at reducing hepatic triglycerides in subjects with NAFLD.
  
  
  METHODS
  Eighteen NAFLD subjects (n = 5 men and 13 women) with a mean (±SD) age of 45 ± 12 y and a body mass index (in kg/m(2)) of 35 ± 7 consumed a carbohydrate-restricted (<20 g/d) or calorie-restricted (1200-1500 kcal/d) diet for 2 wk. Hepatic triglycerides were measured before and after intervention by magnetic resonance spectroscopy.
  
  
  RESULTS
  Mean (±SD) weight loss was similar between the groups (-4.0 ± 1.5 kg in the calorie-restricted group and -4.6 ± 1.5 kg in the carbohydrate-restricted group; P = 0.363). Liver triglycerides decreased significantly with weight loss (P < 0.001) but decreased significantly more (P = 0.008) in carbohydrate-restricted subjects (-55 ± 14%) than in calorie-restricted subjects (-28 ± 23%). Dietary fat (r = 0.643, P = 0.004), carbohydrate (r = -0.606, P = 0.008), posttreatment plasma ketones (r = 0.755, P = 0.006), and respiratory quotient (r = -0.797, P < 0.001) were related to a reduction in liver triglycerides. Plasma aspartate, but not alanine, aminotransferase decreased significantly with weight loss (P < 0.001).
  
  
  CONCLUSIONS
  Two weeks of dietary intervention (≈4.3% weight loss) reduced hepatic triglycerides by ≈42% in subjects with NAFLD; however, reductions were significantly greater with dietary carbohydrate restriction than with calorie restriction. This may have been due, in part, to enhanced hepatic and whole-body oxidation. This trial was registered at clinicaltrials.gov as NCT01262326.
authors.affiliation: Departments of Internal Medicine, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA. jeffrey.browning@utsouthwestern.edu
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Browning
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Baker
authors.forename: Thomas
authors.initials: T
authors.lastname: Rogers
authors.forename: Jeannie
authors.initials: J
authors.lastname: Davis
authors.forename: Santhosh
authors.initials: S
authors.lastname: Satapati
authors.forename: Shawn C
authors.initials: SC
authors.lastname: Burgess
mesh_terms: D000328:Adult; D015992:Body Mass Index; D050528:Diet, Carbohydrate-Restricted; D004038:Diet, Reducing; D005234:Fatty Liver / Q000097:blood / Q000178:diet therapy*; D005260:Female; D006801:Humans; D007659:Ketones / Q000097:blood; D008099:Liver / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D014280:Triglycerides / Q000378:metabolism*; D015431:Weight Loss
chemical_list: D007659:Ketones; D014280:Triglycerides